Effect of particle reinforcements on the texture and dislocation activities of magnesium matrix composites

Abstract

The introduction of ceramic particles into magnesium (Mg) alloys not only leads to a grain refinement effect but also influences their texture. However, dislocation activities within the Mg matrix resulting from these effects remain unclear. In this study, in-situ tensile testing combined with synchrotron radiation techniques was utilized to investigate the microstructure, load partitioning, and dislocation density evolution of SiC_p/Mg–5Zn and Mg–5Zn samples under different tensile strain conditions. It was found that more dislocation slip systems were involved in the SiC_p/Mg–5Zn composite during deformation, whereas the Mg–5Zn alloy exhibited a higher capacity for dislocation accumulation. By an elasto-plastic self-consistent (EPSC) model and a full-field crystal plasticity finite element method (CPFEM) simulation, the pyramidal <c + a > dislocation activity was identified after a 2 % strain in the SiC_p/Mg–5Zn composite. This was accompanied by the load transfer between α-Mg grains as well as regions with different SiC_p volume fractions. Additionally, a novel texture formation mechanism was proposed to explain the texture characteristics of Mg matrix composites (MMCs). The strengthening mechanisms induced by reinforcements were also quantified.